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How do you measure the INSIDE of a bottle?

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  • 3illmesmart
    replied
    Old school...
    https://www.generaltools.com/12-in-inside-caliper
    I'm going to guess you could measure the outside caliper left sticking out with this, might need a bigger set...
    http://www.timberbits.com/robert-sor...tside-calipers

    Leave a comment:


  • 3 Phase Lightbulb
    Guest replied
    I gather a Genie could measure the inside of the bottle for you.

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  • PStechPaul
    replied
    First thing I thought of was using capacitive sensing:

    https://en.wikipedia.org/wiki/Capaci...acement_sensor

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  • boslab
    replied
    A measuring pin can be made of rod, think Allen key, fit into or onto height guage, stick offending pipe on a vee block, insert the measuring pin touch where your interested, you get the idea.
    I have done the same measuring inside rollers you can access the bottom of the roller outside, then you have the height inside, one subtracted from the other.
    There's other ways too, two ball bearings and slips between for recesses was handy, similar to internal tapers.
    Mark

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  • Joel
    replied
    If it will work for you, here is a cheap .7 to 1.5" dial bore set for $43 shipped:
    https://www.amazon.com/0-7-1-5-Dial-...Dial+Bore+Gage
    It may only go about 6" deep, though.

    A .7 to 6" set for $100:
    https://www.amazon.com/Anytime-Tools...Dial+Bore+Gage
    Starrett:
    https://www.amazon.com/Starrett-3089...Dial+Bore+Gage

    Leave a comment:


  • Dan Dubeau
    replied
    I'll back that idea too. Every Patternmaker I've ever worked with had gauges like that. 2 arms, a tooling ball for the anvil, and an indicator zeroed on the ball. You can vary the shape of the arm depending on what you want to measure, and how you need to get in there to do it.

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  • rzbill
    replied
    Originally posted by Greg_B View Post
    There is a tool out there called a Magna-Mic. Uses a small ball bearing and a magnetic coil. Calibrated to measure thickness or the gap between the ball and the coil on non-magnetic stuff. Glass, plastics etc. Got one at work. We use it to measure the wall thickness of plastic bottles we mold.

    There are also Ultrasonic versions, but I have no experience with them.
    Greg has identified the common standard in the food packaging industry for measuring wall thickness of containers that are otherwise difficult to access in an NDT manner. Unfortunately, they are grossly expensive for the hobbyist or small business owner. Interesting post from Wombat that suggested making one using root principles. Try to keep that one in the back pocket for the future. However, I have never used them on a metalic container, only plastics so I do not know how the Magna-mic would work with a conductive container.

    On other machined parts that were difficult to access, we used a comparator and a double probe. One end of the probe went into the part and the other end stayed out in the open where it could be shadowed against a profile placed on the comparator screen.

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  • BCRider
    replied
    That's the same idea I was suggesting too. But with an angle or more open radius on the bend for the elbow if needed to get in through the opening.

    But so far we still don't know if the aim is to check inside diameter, inside length or wall thickness.

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  • J Tiers
    replied
    Softtail has it.

    One arm into the "bottle", and the indicator on the other. Make so the indicator zeros on the arm

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  • wombat2go
    replied
    Yes Greg, could also be a home brew magnetic method:
    Make 2 ferrite cored cylindrical coils of diameter about the wall thickness. The outer coil will be the field coil.
    The outer coil will be a long solenoid ( length > 3 times diameter.)
    The inner sense coil can be shorter and can have a bullet nose for better positional accuracy.
    Excite the outer field coil, and feed the inner sense coil to o'scope.
    Firstly calibrate for axial distance as a function of sense voltage.
    Then insert the sense coil in the bottle, find the peak voltage and infer the wall thicknesses.

    The sense voltage varies by the square of the wall thickness so the measurement should be sensitive.
    ( Accuracy will depend on some mechanical details)

    I have not done this, but I spoke to a Canadian person one time who was doing it, to measure distance , and also metal conductivity.

    Leave a comment:


  • Greg_B
    replied
    There is a tool out there called a Magna-Mic. Uses a small ball bearing and a magnetic coil. Calibrated to measure thickness or the gap between the ball and the coil on non-magnetic stuff. Glass, plastics etc. Got one at work. We use it to measure the wall thickness of plastic bottles we mold.

    There are also Ultrasonic versions, but I have no experience with them.

    Leave a comment:


  • BCRider
    replied
    Lots of options so far for measuring a variety of things. Are you after ID, volume or wall thickness? You didn't state that in the first post. And so far I've seen options for all three in the replies.

    For ID I'm thinking that a set of the old sprung arm style inside calipers with the little adjustment screws could be modified with some heating to alter the shape of the arms so you can get in through the end opening and feel the size at some location. Then without turning the adjustment screw compress the arms back and withdraw the caliper and then measure the spread with dial or digital calipers or micrometer. With only a little care and practice you can get to within 3 to 5 thou easily. And closer to a couple of thou with a little practice at getting the feel just right. Very old school method that worked for most of the industrial revolution until someone gave us internal mics and spring loaded bore gauges.

    For wall thickness it would not take a lot of effort to make up a long "U" shape with a dial gauge on one arm and the other bent inwards to form a dogleg to get around the neck and let you measure the wall thickness directly. Sort of like a sheet metal or fabric dial based thickness gauge on steroids.

    Leave a comment:


  • gambler
    replied
    Originally posted by Rich Carlstedt View Post
    Cheap quick test ?
    tool under one dollar ?

    get a balloon from a party store -not a large one !

    Slip the balloon neck onto a piece of tubing -tightly

    Stick the balloon into the bottle and inflate. You will see when the rubber touches the sides of the bottle and then stop and pinch off the tube and pull it out of the bottle and measure the diameter

    Rich

    OK, Maybe this is not a glass bottle, then read the following post !
    freeze water in tube remove and measure

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  • Rich Carlstedt
    replied
    Ok, I was thinking of the title when I used a bottle in the above post ...maybe this is metal and not visible ..if so here is another easy method but may be $
    Do you have a Blake Center finder or a dial test Indicator with a large range ?

    if so, then you should be able to test the "bottle in a lathe or mill.
    Chuck the bottle in a 3 jaw and mount the Blake in the tailstock.
    Using a long bent probe (5-6") introduce the probe through the neck and into the bottle.
    Now rotate the bottle and record the readings and the lateral location.
    Remove the part and check the calibration readings of the Blake to see what the ID's are.

    Rich

    Leave a comment:


  • Rich Carlstedt
    replied
    Cheap quick test ?
    tool under one dollar ?

    get a balloon from a party store -not a large one !

    Slip the balloon neck onto a piece of tubing -tightly

    Stick the balloon into the bottle and inflate. You will see when the rubber touches the sides of the bottle and then stop and pinch off the tube and pull it out of the bottle and measure the diameter

    Rich

    OK, Maybe this is not a glass bottle, then read the following post !
    Last edited by Rich Carlstedt; 03-21-2018, 02:38 PM.

    Leave a comment:

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